Cranberry Juice – Can it Cure or Prevent Cystitis?

For several decades now there has been a health rumour circulating that cranberry juice can cure urinary tract infections (cystitis) or have a preventative effect in those who tend to suffer multiple attacks. Such health rumours are extremely popular with the “health columns” of many newspapers and magazines. There is an obvious appeal in the idea that something natural and fruity will act like a medicine. But is there any evidence to back these claims?

If you want to know the answer to questions like this, the oracle is Cochrane. Many scientists publish reviews of literature. Sometimes they are thorough. Sometimes they are biased in support a particular theory. The Cochrane Collaboration, on the other hand, publish systematic reviews. These are exhaustive examinations of the literature carried out by volunteers from the ranks of medical scientists. They leave no stone unturned in their search for studies. Then they select the studies that involve well-conducted trials (randomised, controlled trials with a placebo) on human beings. They look at these carefully and determine whether the sum of the results tend to show any clear evidence.

The fact that they look at human studies is important. Lab data from cells in dishes or from mice are often cited but neither of these tell you whether something works in a human being. In the case of cranberries there is some lab evidence that cranberry juice contains a chemical that can discourage bacteria from sticking to the wall of the bladder. But does this translate into practice?

In a recently updated Cochrane review the authors failed to detect any clear effect of cranberry products in preventing cystitis in susceptible people. In a review in 2010 the Cochrane team found no well-conducted studies on cranberry products as a treatment.

There was a problem with a high drop-out rate from the studies. Consuming cranberry juice in sufficient quantities, every day, to maintain a high level of cranberry chemical in your urine is not easy. The juice is acidic and sugary. The implications for dental health are obvious and as I posted previously, consuming a lot of juice is not necessarily a Good Thing.  

If you don’t want to read scientific reviews and you’re wondering whether some food or drink has a proven health benefit, I suggest you read the packaging carefully. It may refer vaguely to something that sounds healthy – but does it clearly say there is a proven benefit to a specific aspect of health? If not, you can be confident that no convincing case has been made to the regulatory agencies.

There is a long list of food products that would dearly love to prove they have health benefits but the list of those that do is an extremely short one.

http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD001321.pub5/abstract

http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD001322/abstract

http://www.cochrane.org

A Healthy Glass of Juice?

I'm going to stay with the vitamin C theme and talk about fruit juice. It is a delicious drink, particularly freshly-squeezed orange juice. But it is also a triumph of marketing.

In the Second World War the British Ministry of Food worried, probably unnecessarily, that children would be deficient in vitamin C. Fresh, imported fruit was rare but people did consume quite a lot of vegetables - so their vitamin C consumption was probably fine. But juice drinks were recommended for children as a supplement. Blackcurrants and rosehips were home-grown sources of fruit concentrate. Those of us who grew up in the post war decades remember concentrated orange juice from the NHS clinic. 

Meanwhile the orange growers of Florida were promoting orange juice, and doing so very successfully. OJ, as it became known, became a standard part of the diet in the United States. Every good mom dispensed it liberally. I visited Las Vegas once and it was being doled out to breakfast-buffet-eaters by the pint. As soon as your glass was nearly empty, someone would offer to fill it.

Since then fruit juice in various forms has become a regular feature in most British shopping trolleys. It maintains an image of being a healthy drink, riding on the back of the stellar success of vitamin C. (see previous post)

But is it really healthy?

The recommended daily intake of Vitamin C varies between countries but is always under 100mg. A 250ml glass of vitamin C contains about 120mg of vitamin C, more than our daily requirement. How much is 250ml? It is an American 'cup' or a large wine-glass full. It may contain a few other useful micronutrients but it also contains a lot of sugar.

Every 250ml glass of unsweetened juice contains the equivalent of 8 teaspoonfuls of sugar - similar to non-diet cola. And this of course accounts, in part, for its success. From cradle to grave we adore sweet things. And the more we eat, the more we crave.

Dentists disapprove of regular juice consumption - the sugar encourages decay and the acidity of the juice erodes enamel.

Dietitians are not keen either - they grudgingly allow that a small glass of juice can be counted as one of your "five-a-day". Their recommended serving is 150ml. In other words a small wine glass size. You can't achieve your five-a-day target by drinking 750ml of juice. You can only count one.

Increasing rates of obesity and type 2 diabetes are undoubtedly fuelled by consuming sugar and there is no reason to think that sugar-laden juice is somehow exempt from blame. The fact that it claims to be healthy perhaps makes it more culpable. There is no reason to think juice, in anything other than small quantities, is a good choice if you are trying to eat a healthy diet.

What about "juicing" then? It is quite entertaining, if you have a cheap source of fruit and a user-friendly machine. But is it "healthy"? I suggest that if you have a sick person to look after, one who is not eating well for more than a couple of days, then juicing may have a role - fresh juice offers palatable fluid and calories if calories are a priority.  But the idea that it is otherwise beneficial to health has no foundation.

Milk, water and unsweetened teas are better ways of consuming fluids than any form of sweet drink. Vitamins are better obtained by eating a variety of whole fresh fruit and vegetables. If you want to a citrus-flavoured drink when you have a cold, consider options that don’t contain lots of sugar - fruit or ginger tea bags, sweetened with just a little honey or marmalade.